In this paper, we present a four-layered representing architecture for the configurations of a link-type reconfigurable mobile robot. Decimal numbers are used to represent all these possibilities in joint space. Binary codes are introduced to represent the links with consideration of adjacent interventions. To find out all the mobile configurations completely and accurately, configuration matrices are proposed to represent the configurations physically and to detect the multi-module interventions. Lastly, we take a three-module self-reconfigurable robot, AMOEBA-I, as an example to validate the proposed four-layered approach.